34 THE RED BLOOD-CORPUSCLES. 



The red blood-corpuscles are characterized by their great elasticity, 

 flexibility, and softness. 



THE RED BLOOD-CORPUSCLES (ERYTHROCYTES). 



Individually the red corpuscles are of a yellowish color with a greenish 

 tint. They are unprovided with either capsule or nucleus, but consist 

 throughout of a homogeneous mass. This consists (i) of a framework 

 of exceedingly pale, soft protoplasm, the stroma or cytoplasm, and (2) 

 of the red blood coloring-matter, the hemoglobin, which impregnates 

 the stroma (like paraplasm), in the same way as a sponge takes up fluid. 



INFLUENCES AFFECTING THE VITAL PHENOMENA OF RED BLOOD- 

 CORPUSCLES. 



Blood-corpuscles retain in unimpaired degree their vital and func- 

 tional activities in shed blood and even in defibrinated blood subse- 

 quently returned to the circulation. Heat has an influence upon 

 their vitality. If blood be heated to a temperature in the neighbor- 

 hood of 52 C. the vital activity of the erythrocytes is destroyed. 

 This fact is evident from the circumstance that the corpuscles in such 

 blood are soon dissolved when returned to the circulation. Kept in 



FIG. 4. Red Blood-corpuscles: a, b, normal human red corpuscles, the central depression more or less in focus; 

 c, d, e, mulberry, and g, h, crenated forms; k, pale corpuscles decolorized by water; 1, stroma; f, frog's blood- 

 corpuscle acted on by a strong saline solution. 



the cold in a flask exposed to the influence of ice-water mammalian 

 blood may retain its functional activity for 4 or 5 days. Removed 

 from the body for a longer period of time and then returned to the cir- 

 culation the red corpuscles rapidly undergo destruction an evidence 

 that they have lost their vital activities within this time. 



The erythrocytes in blood recently removed from a vessel frequently 

 exhibit changes in form that result in their assuming a mulberry-like 

 appearance. These have been attributed to active contraction on the 

 part of the stroma. Nevertheless, it must as yet be considered doubtful 

 whether this is to be looked upon as an obvious vital phenomenon. 

 It is true, however, that Max Schultze has observed active contractility 

 and motility in the red blood-corpuscles of quite young embryo 

 chickens. In support of the vital activity of the red corpuscles the 

 fact may be cited that certain substances dissolved in the plasma are 



